Hello,

Here is what happens with most recent zsh snapshot.

./D07multibyte.ztst: starting.
Testing multibyte with locale en_US.UTF-8
*** buffer overflow detected ***: ../Src/zsh terminated
======= Backtrace: =========
/lib/libc.so.6(__chk_fail+0x41)[0x401552a1]
/lib/libc.so.6[0x40154ae8]
/lib/libc.so.6(_IO_default_xsputn+0xa7)[0x400e9407]
/lib/libc.so.6(_IO_vfprintf+0x1a07)[0x400c4697]
/lib/libc.so.6(__vsprintf_chk+0xab)[0x40154b9b]
/lib/libc.so.6(__sprintf_chk+0x30)[0x40154ad0]
../Src/zsh[0x80a5a97]
../Src/zsh[0x80a969b]
../Src/zsh(prefork+0x69)[0x80ab309]
../Src/zsh[0x80671f0]
../Src/zsh[0x80692e9]
../Src/zsh[0x80696c9]
../Src/zsh(execlist+0x33a)[0x806a39a]
../Src/zsh(execfor+0x21e)[0x808592e]
../Src/zsh[0x8068442]
../Src/zsh[0x8069574]
../Src/zsh[0x80696c9]
../Src/zsh(execlist+0x33a)[0x806a39a]
../Src/zsh(execode+0x3a)[0x806a65a]
../Src/zsh(bin_eval+0x88)[0x8053e08]
../Src/zsh(execbuiltin+0x5a3)[0x805b733]
../Src/zsh[0x8068e9a]
../Src/zsh[0x80692e9]
../Src/zsh[0x80696c9]
../Src/zsh(execlist+0x33a)[0x806a39a]
../Src/zsh(execode+0x3a)[0x806a65a]
../Src/zsh(runshfunc+0xd1)[0x806a741]
../Src/zsh(doshfunc+0x34e)[0x806aabe]
[...]